Total load on a truss

[kevin.hayward]

I have a length of truss. Lights, breakout boxes, cables are placed. I've been asked to create a report of the total weight of all these parts.

 

Trouble is, I only have four months experience with VW (over 30 yrs with that other CAD program that shall not be named).

 

Spotlight>Reports>Create Reports has an option to use preformatted reports, but "weight of kit on a truss" isn't there, which is odd as I thought it would've been such a basic question.

 

Does anybody have a link to one I can load into my project?

[Scott C. Parker]

Are you familiar with Autoplot by @Sam Jones? He has a script to do exactly what you're looking for. I used it in all of my event drawings when doing rigging work. I made a video before joining VW.

[Steven Morgan]

I would also recommend AutoPlot which does this very easily. But using built in tools I would make the truss a Hanging Position and attach all the objects to it. You will then see the "Total Hung Weight" of the Hanging Position. From there you can run a report showing each hang position and its weight. 

[Sam Jones]

@stevenmorgan94method will work well, but only with objects that are recognized by the Hanging Position.  The AutoPlot (AP) command will list every object that is selected and its weight.  It will flag objects that have no listed weight and allow you to enter a weight value to be included in the weight total if you wish.  Also it is unclear to me how the Total Hung Weight  field collects weight for Video Screen and Blended Screen objects.  Below is a screen shot of worksheet created by the AP command.  I have also attached the command here.  You will need to put it in the Plug-Ins folder that is inside your user folder and then add it to your workspace.  The command should be fully functional for 2 months after you install it.  You can download the full suite of AP commands at www.autoplotvw.com.  Drop me a note if you have any questions or problems.

 

Sam

sjones@autoplotvw.com

 

AP Collect and Total Weight.vsm

 

 

 

[JBenghiat]

I'll also plug my Savvy Position Label. One of the options for the Notes field is a display of total hung weight for the position, which includes every object attached to the rigging object as a load. It works with Hanging Positions, Lighting Pipes and Ladders, Straight Truss, Curved Truss, Truss objects, Truss lines, and Truss systems. The result only appears as a note in the positions label -- if you need a report, AutoPlot is the way to go.

https://benghiatlighting.com/software/product/position-label/

[kevin.hayward]

@Sam Jones I'm trying out your plugin. It appears to do what I want, but there seem to be some limitations. It doesn't pick up cable ID, nor the cable weight.

 

I suspect the cable weight is calculated by ConnectCAD. Am I correct? If so, it's another reason to pester the boss to buy CC.

 

How do I get the table to pick up Cable IDs properly?

 

What this promises looks good, but I can't quite justify buying it to my boss yet.

 

Thank you

[Sam Jones]

If you are using the new Power Planning cables, you are correct; the command is not reporting the Cable Run ID correctly.  The same is true for legacy cable objects like the Multicable.  The cable ID fields will need to be specified in the code of the command, and I will fix that today.  If you are using another cable object, I would need to know what that is.  Objects that the command does not explicitly know about will only have a field called "ID" reported, but I would be interested in collecting other VW ID field names.

As for cable weight, that is a whole other matter.  It is unlikely that cables will have any weight values to retrieve other than a "distributed weight" value like 0.74 lb/ft.  There is no way for the command to know how the cable weight is distributed, for example how much is laying on the cable, how long the cable drop is if it exists, or how the weight is distributed by any cable pickup.  You are going to need to figure out cable weights yourself and plug those weights into the worksheet.  I doubt that ConnectCAD computes cable weights.  It would need an undetermined number of fields to report different weights on different hanging positions that the cable path would run.  If this is all a deal breaker for you, so it goes, and keep us informed as to the results of your quest for automatic cable weight reporting.  It is possible that the new power planning cable will report weight to Braceworks in the future, but I am not seeing that happening yet.

If you want to Zoom and talk about all of this, I'm in LA and 8 hours behind UK time, but I'm nursing a broken foot and can talk any time after 3PM UK time

 

Sam

sjones@autoplotvw.com

[Peter Neufeld.]

Hello,

I give this data tag out to our users that dynamically calculates the weight of Hanging Positions. I've placed some cables on and it seems to calculate those.

 

 

Data Tag Example v2023.vwx

 

Cheers,

Peter

[Sam Jones]

@Peter Neufeld.Your example didn't show any cable on the truss.  Can you post an example with cable?  I tried to add cable, and I couldn't even get the Hanging Position to recognize that the cable was on it.  I'm not familiar with the new Power Planning cables, so I probably got that wrong.  All other kinds of cable are transparent to Hanging Positions and are not reported in the Total Hung Weight.

Thanks.

[Peter Neufeld.]

Hi Sam,

Here's a quick movie:

 

 

 

 

 

Cheers,

Peter

 

 

 

 

[Sam Jones]

Peter,  your example shows that the entire cable rests on the single hanging position.  This is only true for jumpers and data between fixtures.  That condition is almost never true for multicables and other home runs.  Additionally, if such a multi is dragged onto a hanging position such that only part of the cable run is actually on the position, the Hanging Position and its data tag will both report an incorrect total hung weight.  At this time, reporting cable weights on a truss can only be done by manually measuring the portion of each cable that is on a hanging position, computing the weight for those portions and entering that value somewhere to be used.  For 3 or 4 -  6 circuit mults the weight difference may not matter, but for some of the movie cable waterfalls that I have been told about, the difference would be enormous.  I have even been told about corporate shows with a similar problem.  I don't think cable weights will be reported automatically and accurately for quite some time.  I would be very pleased to be proven wrong.

Even now, a Hanging Positions "Total Hung Weight" requires that the position be carefully constructed and everything hanging from it be carefully constructed or represented with separately placed dummy loads.  In the absence of any of that, the "Total Hung Weight" parameter may or may not be of any use.

 

[Peter Neufeld.]

Hi Sam,

You make some good points. I suppose if the cable was picked up one end by a cable pick then the data tag readout would be pretty truthful but I'm no engineer. If it's just like a 'waterfall' drop to the deck off one end (as you nicely describe) then of course it is beyond what a data tag could know about. However in that case one might just add a point load. It wouldn't be that hard to work out how much a multicore with a 10m drop x a dozen others might weigh.

 

That's by the by. I give out this data tag simply because only Hanging Positions are able to give out the weight unlike other rigging objects and I hope it is useful for users.

 

Cheers,

Peter

[JBenghiat]

I believe there's actually a bug in the Cable object. The total weight isn't defined properly for Braceworks, so it gets set correctly when a cable style is selected, but then the weight per length gets calculated from the total weight, instead of the other way around. It also means that the weight of the cable won't show up in any total hung weight calculations.

 

I believe if the object were working properly, it would show up in a Hanging Position's total weight. As for Sam's point's, while I can only speculate on the engineering perspective, when we calculate a total hung weight, we're looking for a maximum limit rather than a snapshot of the position's actual weight. Calculations for motors, rigging points, hardware, etc. should assume that the entire weight of the cable applies to the position. And certainly, worst-case-scenario is that the cable is attached to a position coiled and hoisted into place before being deployed.

[Sam Jones]

In almost all things VW, I will defer to Josh, but

 

2 hours ago, JBenghiat said:

etc. should assume that the entire weight of the cable applies to the position.

 

Sorry.  No.  Hard stop.  From dimmer beach to FOH?  Things are getting better with  LEDs; not enough better.  If you really think this is up for debate, I'll do that, but for now, no.  Hard stop.

 

[kevin.hayward]

At the moment, I only have stage boxes, lights and cables between them on the truss. I only, for now, need to report those weights.

 

I presume that the supply cables to the truss will be calculated later.

[Bill_Rios]

I would love to know if anyone has figured out a way to make the hanging position report total weight report minus pipe weight.

Thinking batons in a theatre where pipe weight is already calculated.  I just need the load, not the pipe.

Also, using schematic views has pushed me away from using Hanging positions and into leaving them as rigging objects.  Rigging objects had a record format with a field for total weight, but it seems to be a user generated field.  Is there a way to make VW auto fill that info with weight form loads attached to the rigging object?

 

Thanks!

 

Edited August 8, 2023 by Bill_Rios